For judging whether a sample seal-imprint is the same as a registered one, the sample or the registered imprint is displaced or rotated before verification since a sample seal-imprint may have been sealed with a different posture from that of the registered one. The distance and directions of the movement must be calculated first in order to verify a seal-imprint. Conventionally, a sample seal-imprint is moved relative to the registered one so that an identification ratio becomes a maximum. Then the postures of the sample and registered one are deemed to be the same.